In a generator, motor, or other rotating electrical device, i.e., a dynamoelectric machine, insulation is disposed about field end windings, for example, about the rotor end, forming a rotational part of the dynamoelectric machine. The insulation is usually provided by sheets of glass epoxy laminate disposed in concentric layers about the rotating part. The sheets, e.g., Mylar, from which the laminates are formed, are typically provided cut to size in a flat condition and delivered to an assembly area. The flat sheets are conventionally of a size to overlie substantially about one-half of the circumference of the rotating part so that each concentric layer is comprised of two flat sheets molded into a semi-circular configuration. Initially a resin layer is applied between the sheets and the sheets are then placed into a half-cylindrical mold. Either hot or cold molding processes may be used to form the half-cylindrical insulation sheets. To assemble the molded sheets onto the rotational part, e.g., the rotor end, the sheets are held about the part by taping each layer and building up the insulation laminate. While this process has been used, it has been found that the resin used to impregnate the glass cloth gives off noxious fumes when the retaining ring of the dynamoelectric machine is shrink-fitted about the insulation laminate.
Another method for forming the insulation laminate about the rotational part involved taping flat insulation sheets about the part. The stiffness of the flat sheet insulation, however, required substantial quantities of tape to hold the flat sheets in the generally semi-cylindrical configuration. So much tape was required, however, that a layer of insulation could be lost in the multiple concentric layers of insulation. This method of installation is also time-consuming and presents a safety hazard because the sheet material will spring back into its flat condition with considerable force, unless restrained. Consequently, by bending the insulation material and attempting to hold it in place while fixing the material about the rotary part, there is presented substantial hazard to the installers should the material spring back into a flat condition. Moreover, excessive assembly time is required to manipulate the flat sheets and assemble them in their stressed or biased condition to form the numerous concentric layers of insulation material about the cylindrical part of the machine.